Non-galling alloy



United States Patent 3,072,477 NON-GALLING ALLOY William J. Parana, Waukesha, Wis., assignor to Waukesha Foundry Company, Waukesha, Wis., a corporation of Wisconsin No Drawing. Filed Dec. 7, 1959, Ser. No. 857,558 5 Claims. (Cl. 75-470) lhis invention relates to a non-galling alloy useful in hearings to permit relatively high bearing pressure with minimum wear.

The alloy wherein disclosed is an improvement for these purposes upon the alloy disclosed in Thomas Patent 2,482,382, granted September 20, 1949. The desired alloy is corrosion resistant, as is the alloy in said patent, and has superior anti-wear properties and a compressive yield strength above that of the patent without sacrifice of the non-galling characteristics.

Like the alloy of the Thomas patent above identified, the present alloy is particularly suited for use in dairy equipment and other food industries in which bearings are required to be free of copper and iron, the present alloy having the advantage of providing bearings for this service with superior tensile strength and reduced yield and elongation as well as increased hardness.

Extensive research shows that the character of the mating parts is a very important factor in relative wear. A bearing made hard either by hardening its surface or by using hard materials is of limited value because of a tendency to produce excessive wear in the mating part. On the other hand, if an attempt is made to reduce wear merely by introducing soft particles, the bearing material is itself subject to rapid Wear when the pressure exceeds the relatively low compressive yield strength of the matrix.

The alloy of the present invention provides a corrosionresistant non-galling nickel base material which is hard enough to resist deterioration by wear and at the same time minimizes wear on the complementary part which bears upon it. The matrix of the alloy of this invention is hardened either by the use of carbon or by the use of beryllium or by the combination of carbon and beryllium. Hardening the matrix increases the compressive yield strength and accordingly raises the maximum allowable contact pressure while the lead particles in the matrix provide the non-galling properties.

The amount of carbon and/ or beryllium added to the alloy hardens the matrix in direct proportion to the amount added. However, the carbon is not added to provide lubrication, as in the production of graphitic nickel. In graphitic nickel, free graphite is required and sufiicient carbon is added, in excess of one percent, so that particles of carbon are rejected by the matrix.

For the purposes of the instant invention the amounts of hardening agent are varied directly with the hardness required to resist the contact pressure on the hearing. The maximum amount is so determined as to keep the matrix softer than the mating part.

The microstructural analysis of the alloy of the present invention shows that there is little or no free carbon in the matrix, all of the carbon being in solution and there being no difference in microstructure between the alloy of the present invention and that of the patent above identified. However, one alloy made in accordance with the present invention shows a Brinell hardness of 220 as compared with Brinell hardness of approximately 158 for the alloys disclosed in Patent 2,482,382.. The wear of a bearing madeof an alloy according to the present invention is only about one-sixth as great as the wear of a bearing made from a commercial alloy produced under said patent.

3,072,477 Patented Jan. 8, 1963 The addition of beryllium also hardens the matrix and increases the compressive yield strength. Beryllium may be used with or Without carbon, Ordinarily it is not used alone but is desirably used in addition to carbon when very high wear strength is required.

The preferred ranges of the components of the present alloy are as follows, the figures given being percentages by weight:

Lead 3-5 Zinc 6-9 Tin 7-9 Manganese 1.52.5 Carbon .05.30 Beryllium .l0.50 Nickel Balance It will be understood that, as in the patent above mentioned, manganese may be omitted and nickel substituted therefor if the alloy is not to be cast. It is further to be understood that while beryllium is preferably present in the minimum amount of .l%, it may be omitted completely as in Example 2, given below.

A specific example of a desirable alloy embodying the present invention is as follows:

Example 1 Lead 4 Zinc 8 Tin 8 Manganese 2 Carbon .25 Beryllium .15 Nickel Balance Another specific example of an alloy embodying the present invention and omitting beryllium is as follows:

The alloys of the present invention are found to have particularly desirable and superior bearing properties at high temperatures.

The physical properties of an alloy with composition within the preferred ranges are:

Tensile strength p.s.i -90,000 Yield (.2% offset) p.s.i 6575,000 Elongation (percent) (in 2inches) 3-6 Hardness (Brinell, 3000 kg.) -250 What is claimed is:

l. A corrosion-resistant, non-galling bearing alloy for use in food processing machinery and the like, said alloy comprising a matrix which is predominantly nickel and additionally consisting essentially of zinc and tin in proportions approximating 6% to 9% by weight of zinc and 7% to 9% by weight of tin, and containing a matrixhardening agent selected from a group consisting of carbon, beryllium and the combination of carbon with berylliurn, carbon being present in the" approximate proportion of .05 to .30% by weight and beryllium in the approximate proportion of .1 to .50% by weight, said alloy having lead distributed in the matrix in the form of soft particles and in proportions approximating 3% to 5% by weight.

2. An alloy according to claim 1 in which the alloy is castable and contains beryllium in the approximate proportion of .10% to .5% by weight.

3. An alloy according to claim 1 having approximate composition by weight of lead 4%, zinc 8%, tin 8%, manganese 2%, carbon .25%, beryllium .15%, the balance being nickel.

4. An alloy according to claim 1 having approximate References Cited in the file of this patent UNITED STATES PATENTS 2,289,566 Adomoli July 14, 1942 2,482,382 Thomas Sept. 20, 1949 FOREIGN PATENTS 115,212 Australia May 26, 1942 

1. A CORROSION-RESISTANT, NON-GALLING BEARING ALLOY FOR USE IN FOOD PROCESSING MACHINERY AND THE LIKE, SAID ALLOY COMPRISING A MATRIX WHICH IS PREDOMINANTLY NICKEL AND ADDITIONALLY CONSISTING ESSENTIALLY OF ZINC AND TIN IN PROPORTIONS APPROXIMATELY 6% TO 9% BY WEIGHT OF ZINC AND 7% TO 9% BY WEIGHT OF TIN, AND CONTAINING A MATRIXHARDENING AGENT SELECTED FROM A GROUP CONSISTING OF CARBON, BERYLLIUM AND THE COMBINATION OF CARBON WITH BERYLLIUM, CARBON BEING PRESENT IN THE APPROXIMATE PROPORTION OF .05 TO .30% BY WEIGHT AND BERYLLIUM IN THE APPROXIMATE PROPORTION OF .1 TO .50% BY WEIGHT, SAID ALLOY HAVING LEAD DISTRIBUTED IN THE MATRIX IN THE FORM OF SOFT PARTICLES AND IN PROPORTIONS APPROXIMATING 3% TO 5% BY WEIGHT. 